Regarding a related inlet, Japanese Patent Application Publication No. 2011-238529, for example, describes a power supply plug lock device that is aims to make a lock operation an operation according to an intent of a user (Patent Document 1).
In the power supply plug lock device described in Patent Document 1, a charging system for charging a battery is provided in a hybrid-type vehicle. A power supply plug having a nozzle shape is provided on a power supply side of the charging system, and a charging connector is provided as a connecting location of the power supply plug on the vehicle side. An inlet is provided as a connecting port for an electric terminal of the power supply plug, in the charging connector, and a protruding portion is provided on an upper wall surface of this inlet. A lock arm that has a catch is pivotally attached to the power supply plug. The power supply plug is prevented from coming out of the inlet by the catch on the lock arm catching on the protrusion, when connecting the power supply plug to the charging connector.